INFLUENCE OF MOIST HEAT-TREATMENT ON RUMINAL AND INTESTINAL DISAPPEARANCE OF AMINO-ACIDS FROM CANOLA-MEAL

Three mature Angus steers fitted with large ruminal cannulas and three Holstein steers each fitted with T-shaped cannulas in the proximal du odenum and reentrant cannulas in the terminal ileum were used to study the effect of moist heat treatment on AA digestion of canola meal in each segment of the digestive tract. Canola meal was treated with mois t heat at 127 degrees C for 15 or 45 min. Degradation of AA in the rum en was estimated using small nylon bags incubated for .1, 8, 16, and 2 4 h in the rumen. Digestion of AA in the small and large intestines an d total tract were estimated using separate sets of bags in a sequence of ruminal in situ incubation, in vitro incubation in an acid-pepsin solution, and a mobile bag technique. Heat treatment for 15 or 45 min reduced concentrations of Lys by 15.9 and 29.2% and Arg by 8.0 and 15. 2%, respectively. Heat treatment for 15 or 45 min significantly reduce d the degradation of AA in the rumen; the availability of AA in the sm all intestine increased in proportion to the decreased ruminal degrada tion. Digestion of AA in the large intestine was 5 percentage points h igher after heat treatment for 45 min than with no heat treatment. App arent digestion of AA in the total tract was unaffected by 15 min of h eating; however, 45 min of heating reduced digestion. Moist heat treat ment for 15 min effectively increased ruminal escape of AA in canola m eal, resulting in large increases in AA available for digestion in the small intestine that ranged from 75% for Lys to 154% for His with 16 h of ruminal incubation.